1. Field of the Invention
The present invention relates generally to enclosures deployed in fiber optic communications networks, and more specifically, to an optical connection closure having at least one connector port located in an external wall of the closure operable for receiving a connectorized optical fiber on the inside of the closure and a pre-connectorized fiber optic drop cable on the outside of the closure.
2. Description of the Related Art
Optical fiber is increasingly being used for a variety of broadband applications including voice, video and data transmissions. As a result of the ever-increasing demand for broadband communications, fiber optic networks typically include a large number of mid-span access locations at which one or more optical fibers are branched from a distribution cable. These mid-span access locations provide a branch point from the distribution cable leading to an end user, commonly referred to as a subscriber, and thus, may be used to extend an “all optical” communications network closer to the subscriber. In this regard, fiber optic networks are being developed that deliver “fiber-to-the-curb” (FTTC), “fiber-to-the-business” (FTTB), “fiber-to-the-home” (FTTH), or “fiber-to-the-premises” (FTTP), referred to generically as “FTTx.” Based on the increase in the number of access points and the unique physical attributes of the optical fibers themselves, enclosures are needed for protecting, handling and maintaining optical fibers. Enclosures are also needed for readily connecting branched optical fibers of the distribution cable with respective optical fibers of drop cables to establish desired optical connections, while at the same time providing protection for the access point, the branched optical fibers and the optical connections from exposure to environmental conditions.
In one example of a fiber optic communications network, one or more drop cables are interconnected with a distribution cable at a mid-span access location within an aerial splice closure suspended from an aerial strand or from the distribution cable itself. Substantial expertise and experience are required to configure the optical connections within the closure in the field. In particular, it is often difficult to enter the closure and to identify an optical fiber of the distribution cable to be interconnected with an optical fiber of a particular drop cable. Once identified, the optical fibers of the drop cables are typically joined directly to the optical fibers of the distribution cable at the mid-span access location using conventional splicing techniques, such as fusion splicing. In other instances, the optical fibers of the drop cables and the optical fibers of the distribution cable are first spliced to a short length of optical fiber having an optical connector mounted upon the other end, referred to in the art as a “pigtail.” The pigtails are then routed to opposite sides of a connector adapter sleeve located within the closure to interconnect the drop cable with the distribution cable. In either case, the process of entering and configuring the closure is not only time consuming, but frequently must be accomplished by a highly skilled field technician at significant cost and under field working conditions that are less than ideal. Reconfiguring optical fiber connections in an aerial splice closure is especially difficult, particularly in instances where at least some of the optical fibers of the distribution cable extend uninterrupted through the closure, since the closure cannot be readily removed from the distribution cable. Further, once the optical connections are made, it is often labor intensive, and therefore costly, to reconfigure the existing optical connections or to add additional optical connections.
In order to reduce costs by permitting less experienced and less skilled technicians to perform mid-span access optical connections and reconfigurations in the field, communications service providers are increasingly pre-engineering new fiber optic networks and demanding factory-prepared interconnection solutions, commonly referred to as “plug-and-play” type systems. Pre-engineered networks, however, require that the location of certain of the branch points in the network be predetermined prior to the distribution cable being deployed. More particularly, pre-engineered solutions require precise location of the factory-prepared mid-span access locations where the preterminated, and sometimes pre-connectorized, optical fibers are made available for interconnection with optical fibers of drop cables extending from the subscriber premises. With regard to a factory-prepared interconnection solution, it would be desirable to produce an optical connection closure having one or more connector ports located in an external wall of the closure operable for receiving pre-connectorized optical fibers on the inside of the closure and pre-connectorized fiber optic drop cables on the outside of the closure. It would also be desirable in an FTTP network to provide an optical connection closure that is operable to readily interconnect pre-connectorized fiber optic drop cables with a feeder cable, distribution cable or branch cable of the network. It would also be desirable to provide an optical connection closure within an FTTP network that may be readily reconfigured after installation by a less experienced and less skilled field technician. It would further be desirable to be able to establish optical connections in a fiber optic communications network while eliminating the need for entering the closure and performing splices or adapter sleeve connections after the initial installation.